Question

For the formation of NH$_3$(g) from its constituent elements, which of the relation between the reaction quotient (Q) and equilibrium constant (K$_c$) is correct for the backward reaction?

• A. Q = K$_c$
• B. Q>K$_c$
• C. Q<K$_c$
• D. Q = K = 1

Hint:

If Q>K$_c$: Reverse reaction proceeds.
If Q<K$_c$: Forward reaction proceeds.

Answer 1

The Correct Option is B

For the backward reaction, we must consider that products become reactants and vice versa. If NH$_3$ formation is the forward reaction, then for the reverse, the concentration of products (N$_2$, H$_2$) will be higher initially. If Q (reaction quotient) is greater than K$_c$, it means that more products are present than at equilibrium, and the reverse reaction is favored to attain equilibrium.